Gunko has enough odd aspects that I'd believe Imu's possession is unique to her.
She's the only Holy Knight using Arrows (Just like Imu)
She has the heterochromia
She gave a speech that clearly mirrors both Whitebeard and Law's speech
She's at least in her 70s if not 80s and still young, unlike the other HK we've seen
She has a distinct fear of Nika, which clearly alludes to Imu